A generator set includes a prime mover, such as a diesel or gas engine and a generator that produces electric power. A modern locomotive, among many components, uses a generator set to drive one or more electric motors to move the locomotive and any train cars attached to the locomotive. The prime mover generates mechanical torque which is transferred to the generator to make electrical power that is used to drive the electric motors. Both the prime mover and the generator are attached to a skid or bed using respective feet which are fixed to the skid, typically with bolts.
The driveshaft or crankshaft of the prime mover is mechanically coupled to the armature shaft of the generator either directly or using intermediate parts. Torque is generated at the prime mover during acceleration or normal running. Negative torque may be developed at the generator during engine braking, if used.
As known from simple action-reaction physics, energy in the form of torque that turns the drive and armature shafts must be opposed in an equal and opposite manner. In this case, this opposition force is provided by the housing and feet connections to the skid for both the prime mover and generator. These mechanical attachments keep the prime mover and generator from moving with respect to each other as the energy from the prime mover is transferred via the crankshaft to the generator.
With respect to mounting a prime mover to a generator, EP 1,889,782 (the '782 patent) granted Aug. 26, 2009 to Yanmar Co., Ltd. describes a generator casing that is mounted onto to a gas engine prime mover and around an output drive shaft. The generator casing has stator coils that are mounted in proximity to permanent magnets attached to the output drive shaft. The '782 patent mounts the generator casing directly on the gas engine which requires splines on the output drive shaft for assembly. The '782 patent fails to teach a close coupled adapter that couples a prime mover housing to a separate generator housing while allowing access to the crankshaft connection.